Peripheral neuropathy is associated with a wide variety of causes, including genetically acquired conditions, systemic disease or exposure to toxic agents. It can manifest itself as a dysfunction of motor, sensory, sensorimotor or autonomic nerves.
Among the most important toxic agents causing peripheral neuropathy are therapeutic agents, particularly those used for the treatment of neoplastic disease. In certain cases, peripheral neuropathy is a major complication of cancer treatment and is the main factor limiting the dosage of chemotherapeutic that can be administered to a patient (Macdonald, Neurologic Clinics 9:955-967 (1991)). This is true for the commonly administered agents cisplatin, paclitaxel and vincristine (Broun, et al., Am. J. Clin. Oncol. 16:18-21 (1993); Macdonald, Neurologic Clinics 9:955-967 (1991); Casey, et al., Brain 96:69-86 (1973)). The identification of methods for preventing or alleviating dose-limiting peripheral neuropathologic side effects would allow higher, and more therapeutically effective doses of these chemotherapeutics to be administered to patients, i.e., the therapeutic efficacy of such chemotherapeutics is typically a function of dose and therefore, increasing dosage provides increased patient survival (Macdonald, Neurologic Clinics 9:955-967 (1991); Oxols, Seminars in Oncology 16, suppl. 6:22-30 (1989)).
Beyond the potential for increasing the effectiveness of cancer chemotherapy, the identification of new methods for treating peripheral neuropathy has obvious value in alleviating the suffering of patients with a wide variety of systemic diseases and genetic conditions. In many cases, progressive neuropathy in the peripheral nervous system can be debilitating or fatal.
Although selegiline has been used extensively as a treatment for Parkinson's disease, its effectiveness in the prevention or treatment of peripheral nerve dysfunction caused by toxic agents has not been previously known. The present invention is directed to methods which rely upon this surprising and unexpected discovery to reduce or eliminate symptoms associated with peripheral nerve dysfunction.